Automatic sampler



United States Patent [72] Inventor Trajan Nitescu 723 Riverdale Ave.,Calgary, Alberta, Canada 211 Appl, No. 705,233

[22] Filed Oct. 19, 1967 [45] Patented Oct. 6, 1970 [32] Priority Dec.15,1964

[33] Canada [31] No.9l8,810

Division of Ser. No. 434,882, Feb. 24, 1965, now Pat. No. 3,377,867.

[54] AUTOMATIC SAMPLER 5 Claims, 9 Drawing Figs.

[52] U.S.Cl 137/117, 251/61 2,25l/l22 [51] Int. Cl (105d 11/03,

[50] Field ofSearch 137/117,9; 251/61, 61.2, 26,122, 63.4, 61.1; 138/46[56] References Cited UNITED STATES PATENTS 862,867 8/1907 Eggleston251/61.1 1,685,933 10/1923 Andersson 1 251/28X 2,234,561 3/1941Kittredge 137/9 Primary Examiner-William F. ODea AssistantExaminer-Howard M. Cohru Altorney- Cushman, Darby and Cushman ABSTRACT:A fluid pressure regulator for equalizing the pressure on both sides ofa bleeder point including a pressure sensitive diaphragm which isconnected to the upstream end of the bleeder point. Also included is anoppositely activating pressure sensitive diaphragm connected to thedownstream end of the bleeder point. Between these diaphragms there is ableeder channel, the degree of aperture of which is related to thepressure differential between the diaphragms.

Patented Get. 6, 1970 Sheet Patented Oct. 6, 1970 Sheet 4 0:4

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AUTOMATIC SAMPLER This application is a division of copendingapplication, Ser. No. 434,882 filed February 24, 1965, now Pat. No.3,377,867.

This invention relates to an automatic sampling device for a multiphasenon-homogeneous fluid. more particularly it relates to an automaticdevice for determining the gas-liquid ratio in a multiphase fluid fromproducing oil wells.

At present, the oil and associated gas produced from a well is usuallydirected to a separator where the water, oil and gas are separated,measured independently and then directed to an oil storage center.

a It is an object of one aspect of the present invention to determinethe gas-liquid ratio of a single producing oil well connected in agathering system of producing oil wells.

It is an object of another aspect of the present invention to provide anautomatic sampling device which will determine the gas-liquid ratios ofa composite of periodic samples.

By a broad aspect of the invention there is provided an automaticsampling device for use with a pipe line comprising: a flow dividerhaving inlet means adapted to be connected to said pipe line and outletmeans adapted to be connected to said pipe line downstream of the inletconnection, said flow divider consisting of a plurality of channels oneof which may be connected to a measuring means by means of a valve; saidvalve being capable of being actuated by a conventional timing systemfor the regular periodic sampling of the effluent of said flow channeland a conventional sample measuring means. Preferably, this broad aspectof the invention also includes a pressure stabilizing means forequalizing the flow within the channels of the said flow divider.

By another aspect of the present invention, there is provided a processfor determining the liquid-gas ratio of the effluent flowing through apipe line, comprising: dividing the said effluent into a plurality ofsubstantially identical channels, regularly intermittenly sampling theeffluent of one of the said channels, preferably by taking, during eachsample interval, a volume less than the volume of said channel andmeasuring the liquid-gas ratio thereof. Preferably, also, this processincludes the step of equalizing the flow pressure throughout all of thesaid channels.

By yet another aspect, there is provided a fluid pressure regulator forequalizing the pressure on both sides of a bleeder point whichcomprises: a pressure sensitive diaphragm connected to the upstream endof the said bleeder point, an oppositely activating pressure sensitivediaphragm connected to the downstream end of the said bleeder point anda bleeder channel thcrebetween; the degree of aperture of the saidbleeder channel being related to the pressure differential between thetwo said diaphragms.

In the accompanying drawings:

FIG. 1 is a side, partially diagrammatic view of one embodiment of thesampler connected to an oil well line;

FIG. 2 is a longitudinal cross section elevation of the flow divider andzero differential flow controller and a diagram matic view of the valvemeans;

FIG. 3 is a plane cross section of the flow divider along the lineIII-III of FIG. 2;

FIG. 4 is a central longitudinal sectional view of another embodiment ofthe zero differential flow controller of the present invention;

FIG. 5 is a side partially diagrammatic view of another embodiment ofthe present invention;

FIG. 6 is a cross section of the flow divider used in the embodiment ofthe present sampler shown in FIG. 4;

FIG. 7 is a central longitudinal section, partly in broken lines, of thechannel divider block of FIG. 6;

FIG. 8 is a central longitudinal section of another channel dividerblock used in the present invention; and

FIG. 9 is a longitudinal cross section of one end of an alternativeembodiment of the zero differential flow controller.

FIG. I shows an embodiment of the automatic sampling device indiagrammatic form connected to an oil well line. A bypass line la fromline 1 from the oil well line (not shown) is connected, via valve 1b toa flow divider 2 having a plurality of substantially identical channels.The downstream end of the flow divider is connected via valve 201 tooutlet flow pipe 5 which may in turn be connected to a common oilgathering system (not shown). A valve means 3 such as a solenoidthreeway valve capable of being actuated by a timing circuit shown at 4(and including a switch 4a, a time controller 4b and a battery 4c andelectrical lines 4d leading to solenoid valve 3) is connected to one ofthe channels of the flow divider 2. A bleeder line 6 from valve means 3is connected to the zero differential flow controller 7. Line 8 from theoutlet end of flow controller 7 is connected, preferably through a backpressure regulator 8a to a graduated cylinder 9 which in turn has a gasoutlet 10, provided with a rubber expansion bag 10a connected to a gasmeter 11, which is vented at 11a.

The flow divider 2 and zero differential flow controller 7 are shown indetail in FIG. 2. The by pass line 1 leads into the flow divider 2 whichcomprises a generally cylindrical member 2a provided with internal meansfor divided flow. These means include an orifice plate 12 provided witha central orifice 12a mounted on a screen box 13, provided. with screenapertures 13a and secured to a downwardly depending screw 13b. Screenbox 13 is provided with circumferential O-rings to provide sealingconnection with the inner walls of cylindrical member 7a Resting onledge 2b on the inner wall of cylindrical member 7a is a channel block14. Channel block 14 is provided with a plurality of channels 14a whichare identical in dimension and set in a substantially circular pattern,as can be seen with reference to FIG. 3. All of channels 14a except oneare directly connected through header to exit line 15 which leads tooutlet flow pipe 5 shown in FIG. 1. One channel 14b is connected to exit15 by valve inlet line 21 and valve outlet line 16 through valve means3. When valve means 3 is actuated however, valve inlet line 21 isconnected to bleeder line 6 shown schematically in FIG. 2, which leadsto the zero differential flow controller 7. Cylindrical member 2 isprovided with a top cap 20.

The zero differential flow controller 7 shown in FIGS. 1 and 2 consistsof a main body 7a provided with a longitudinal chamber 7b having twoidentical enlarged opposed end diaphragm chambers 18a and 19a providedwith diaphragms 18 and 19 respectively. Main body 7a is provided with aradial inlet port 25, provided with a reduced inlet channel 25a andradial outlet port 26 leading from an outlet channel 26a Outlet port 3aof solenoid valve 3 is connected, via bleeder line 6 to inlet port 25.Diaphragm 18 is connected by pressure line 20 to valve inlet line 21.Diaphragm 19' is similarly connected by pressure line 22 to valve outletline 16. Two metering rods 22 and 23, connected to diaphragms 18 and 19respectively and provided with reduced diameter tips 22a and 22brespectively are pressed together in narrow butt-to-butt engagement andare slidably fitted in the longitudinal channel 7b by the pressure oftheir respective diaphragms 18 and 19. The pressure differential betweendiaphragms 18 and 19 will determine the position of the metering rodswithin the channel 70 The position which the metering rods so assumedetermines the size of the flow channel between inlet channel 250 andoutlet channel 26a through longitudinal channel 7a i.e., between bleederinlet port 25 and outlet port 26.

The operation of the embodiment of the automatic sampling device ofFIGS. 1, 2 and 3 will now be described. The output from a typical wellis diverted through bypass line 10 by means of opening cutoff valve 1bclosing cutoff valve 10 and passed through flow divider 2. The pipe lineeffluent flows through aperture 12, for proper mixing and into screeningmeans 13 for filtration of solid elements. The flow is then divided intoa large number of streams by means of channels 141:. The oil and gaseffluent then continues into exit 15 and then to outlet flow pipe 5. Thestream flowing through channel 14b normally travels through valve inletline 21 through valve 3 and out valve outlet line 16 tojoin theremaining well output at exit 15. When the valve means 3 is actuatedhowever, the effluent of channel 14b is diverted from valve inlet 21through valve outlet 3a to bleeder line 6 which directs the well sampleto the inlet of zero differential flow controller 7. The sample'is thenpassed through outlet port 26 to a conventional liquid and gas measuringmeans, such as graduated cylinder 9 and gas meter 11, and is then ventedat 11a The purpose of the zero differential flow controller is tonullify any pressure differential between the valve inlet line 21 andthe exit 15. In this way, the flow through channel 14a will be identicalto the flows of the other channels 14 a For example, if the pressure inline and on diaphragm 18 tends to decrease below the pressure in line 22and on diaphragm 19, the flow channel between inlet port 25 to outletport 26 will be restricted in size and thus, the flow will decrease. Bydecreasing this flow, the pressure on diaphragm 18, which is, in fact,the pressure in channel 14b is automatically increased, because of theincreased back pressure in line 6. Similarly if the pressure ondiaphragm 18 is above the pressure on diaphragm 19, the downwardpressure on metering rod 22 will enlarge the passage between inlet port25 and outlet port 26, thus increasing the rate of flow of the sampleand equalizing the flow through channel 14b with the flow through allthe other channels 14a To reflect accurately the pressure at the channel14b exit point and the pressures at exit points of the other channels,it is important to have lines 21 and 16 provided with much largersections than those of channel 141! and 14b. For sampling ef fluentsunder very high pressures, it is preferable to install a back pressureregulator, such as 8a between outlet port 26 and the graduated cylinder9 where the samples are collected.

With the use of a conventional time controller 4b the automatic samplingdevice of the present invention can be set either to take a reducednumber of minute samples or hundreds of such samples during a 24 hourperiod. The number of samples to be taken depends on the homogeneity ofthe effluent to be sampled. For an oil producing well, it is preferredto take from 50 to 500 samples per day, each one of a few secondsduration. The total amount of these collected samples may represent onlyone five-thousandth of the total effluent sampled. Taking as an examplea well producing 100 barrels per day, it will be necessary during a 24hour period to take a composite sample measuring in the aggregate lessthan one gallon.

FIG. 4 shows another embodiment of the zero differential flow control ofthe present invention. The zero differential flow control 200 comprisesa main cylindrical body portion 201 provided with a central longitudinalbore 206, a radial inlet port 202 and inlet channel 203 leading to bore206, and a longitudinally offset radial outlet channel 205 leading frombore 206 to outlet port 204. Bore 206 is provided with an enlargedchamber 207, adjacent outlet channel 205. Within chamber 207 is an uppersealing element 208 and a lower sealing element 209, with a flow channel210 therebetween.

Secured to the upper portion of body 201 is an upper flange plate 211,to which is secured an upper cover plate 212. Upper cover plate 212 alsoanchors the peripheral edge of diaphragm 213. Diaphragm 213 is securedto upper rod 214 by means of lower washer 215, upper ring 216 and nut217. Cover plate 212 is provided with aperture 218 which is adapted tobe connected to the pressure line 20 (see FIG. 1). Thus there isprovided a pressure chamber 219 on which is acting the pressure on theinlet 218.

A similar arrangement is provided at the lower end of body 201, lowerflange plate 211a, lower cover plate 212a. diaphragm 213a, lower rod214a, washer 215a. ring 2160, nut 217a, inlet 218a and pressure chamber2191:. Again, the pressure in the chamber 2190 is equal with thepressure acting through inlet 218a which is adapted to be connected topressure line 16 (see FIG. 1). Rod 214 is provided with a terminalportion of uniformly reduced diameter 220 while lower rod 214a isprovided with a terminal portion 221 of conical configuration. Portion220 abuts portion 221.

As shown in FIG. 4 the pressure acting through inlet 218a is greaterthan the pressure acting through inlet 218. This causes rod 214a to bemoved upwardly to such an extent that there is no flow of fluid betweenbore 206 and chamber 207. As the pressure acting through inlet 218increases rod 214 moves downwardly, thereby permitting fluid to flowfrom bore 206 to chamber 207. This then allows fluid to flow from inlet202 to outlet 204. The connecting channel 222 is provided for theequalization of the pressures on the back side of the diaphragms 213 and213a It is necessary that the pressure acting through inlets 218 and218a be the same. If the pressure acting through inlet 218 should tendto decrease below the pressure acting through inlet, 218a, the flow ofliquid from inlet 202 to outlet 204 is decreased. Conversely, if thepressure acting through inlet 218 tends to increase above the pressureacting through inlet, 218a, the flow from inlet 202 to outlet 204 tendsto increase.

AS shown in FIG. 9, diaphragm 213 may be replaced with bellows 230mounted between a cylindrical tube 231 which is held on rod 214 by nut217, and a clamping piece 232 firmly held between cover plate 212 andflange plate 211. Similarly, diaphragm 213a may be replaced by a bellows(not shown).

Another embodiment of the present invention can be seen with referenceto FIG. 5.

The inflow from a well (not shown) via line 101 is connected to a bypass line 102 and through valve 103 to a sampler 104. The effluent fromsampler 104 is connected via valve 105 and outlet line 106 to main line101. Main line 101 is also provided with a cut off valve 107.

Sample withdrawal port 108 is connected to solenoid valve 109 by a line110. Solenoid valve 109 is actuated by automatic timing circuit 111,consisting of switch 112, time controller 113 and battery 114, andconnected to solenoid valve 109 by electrical lines 115. The outlet port116 of solenoid valve 109 is connected via line 117 to a conventionalsample collecting and measuring equipment 118, which has already beendescribed with reference to FIG. 1 and will not be described again.

The sampler 104 may have an internal construction as shown in FIG. 2 and3. Alternatively, the construction of the channel divider block 99 maybe as shown in the embodiment of FIGS. 6 and 7 or the embodiment of FIG.8. As shown in FIGS. 6 and 7, for example, the channel block 119 of theflow divider 27 consists of a main outer pipe 120 and a plurality ofconcentric pipes 121, 122, 123 and plug 124. The pipes 121, 122, 123 andplug 124 are provided with external flutes 125 running longitudinallyalong the outside of the pipes to provide a plurality of channels 126between the adjacent pipes. The pipes 121, 122, and 123 and plug 124 aremounted within tube 120 by means of upper and lower perforated plates127, whose perforations are in tandem with channels 126, and a snap ring128 holding plate 127 in place. Plate 127 is secured to plug 124 by bolt129. Turbulence may be created upstream of the flow divider throughenlargement in the pipe diameter (as shown in FIG. 4) or by insertion ofan orifice screen box and orifice plate, as shown in FIG. 1. Four of theouter channels 130 of the channel divider block 99 are tapped at 131 toprovide four alternative withdrawal ports 108. Only one of such ports108 is connected to line 110, the other three being normally plugged.Port 108 is normally closed by valve means 109 except during the sampleinterval.

An alternative construction of the channel divider block is shown inFIG. 8. Here, the block is provided with an inlet header chamber and anoutlet header chamber 141. The block 99 is provided with a flange 142 topermit it to be connected to an inlet line, and a flange 143 to permitit to be connected to an outlet line. The channels 143 are provided inconcentric circumferential pattern by drilling channels in the block 99.One of the external channels 144 is provided with a tapped radialaperture 145 to permit it to be connected to line 1 10.

When the automatic timing circuit 111 is actuated, the valve means 109is opened for a predetermined length of time so that the quantity offlowing effluent admitted to the graduated cylinder is less than thevolume of one of the channels 126, 143. The flow within all the channelsof the flow divider is equalized by means of an enlargement of the pipediameter on each side of the sampler 104.

With the present invention oil-producing wells can now be equipped witha meter installed for continuous measuring of the weight of the totaleffluent and a sampler of the present invention for determining thegas-liquid ratio of the effluent. By knowing the gasliquid ratio and thespecific gravity of the gas, oil and water components it is possible tocalculate the amount of oil, gas and water produced at a certain well.In this manner, a large number of wells may be connected to a singlegathering system without requiring an intermediate separating tank. Thetotal effluent can then be directed to a central point where the entireproduction from the large number of wells can be separated into oil, gasand water components and subsequently used in any desired manner.

I claim:

1. A fluid pressure regulator for maintaining the fluid pressure in ableedoff line from a main line at the same value as the fluid pressurein said main line at.a point downstream of said bleedoff line, saidregulator comprising: a housing having a pair of spaced chambers eachaccommodating a pressure actuable member, one of said members beingactuable by fluid pressure in said bleedoff line and the other saidmember being actuable by fluid pressure in said main line downstream ofsaid bleed off line; a bore connecting said chambers; a fluid inletextending into said bore and adapted to be connected to said bleedoffline; a fluid outlet extending into said bore at a point spacedlongitudinally along said bore from said inlet; a shaped rod memberconnected to each of said pressure actuable members and slidable underthe action of its associated member in said bore whereby to provide achamber of varying volume in said bore between said inlet and saidoutlet; the ends of said rod shaped members abutting in said boreadjacent said fluid inlet, whereby rate of fluid entry to said chambermay be controlled; and a pair of sealing elements adjacent said fluidoutlet, axially disposed around said rod shaped member adjacent saidfluid outlet, and provided with a flow path therebetween whereby rate ofexit of fluid from said chamber through said flow path and said fluidoutlet is metered.

2. A fluid pressure regulator as claimed in claim 1 wherein saidpressure actuable members comprise pressure diaphragms.

3. A fluid pressure regulator as claimed in claim 1 wherein saidpressure actuable members comprise bellows means.

4. A fluid pressure regulator as claimed in claim 1 wherein said rodmeans comprises a pair of rods abutting at their ends remote from thepressure actuable means, said remote ends having shaped reduceddimensions.

5. A fluid pressure regulator as claimed in claim 4 wherein said remoteend adjacent said fluid outlet has a conical shape and the remote endadjacent said fluid inlet has a uniformly reduced cylindrical shape.

